Infusion of 5-Azacytidine (5-AZA) Into the Fourth Ventricle in Children With Recurrent Posterior Fossa Ependymoma

Inclusion Criteria: * Diagnosis: Patients with histologically verified ependymoma, with recurrence or progression involving anywhere in the brain and/or spine. To be eligible, patients' disease must have originated in the posterior fossa of the brain. * Patient must have either measurable or evaluable tumor as assessed by MRI of the brain and total spine. * An implanted catheter in the fourth ventricle or posterior fossa tumor cavity attached to a ventricular access device or agreement to have one placed. * A minimum of 7 days between last dose of systemic chemotherapy and/or radiation therapy and first infusion of 5-Azacytidine into fourth ventricle. * Life expectancy of at least 12 weeks in the opinion of the PI * Lansky score of 50 or greater if ≤16 years of age or Karnofsky score of 50 or greater if \> 16 years of age. * Existing neurological deficits must have been stable for a minimum of 1 week prior to study enrollment. * Patients must have recovered from the acute toxic effects of all prior anticancer chemotherapy * Adequate bone marrow function defined by peripheral absolute neutrophil count (ANC) ≥ 500/µL, platelet count ≥ 50,000/ µL (transfusion independent), and hemoglobin ≥9.0 gm/dL (may receive RBC transfusions) * Patient or patient's legal representative, parent(s), or guardian able to provide written informed consent. Exclusion Criteria: * Enrolled in another treatment protocol * Has received another investigational or chemotherapy agent or radiation therap…